1 /*
2 * Copyright 2022 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "Tonemapper.h"
18
19 #include <SkRuntimeEffect.h>
20 #include <log/log.h>
21 // libshaders only exists on Android devices
22 #ifdef __ANDROID__
23 #include <renderthread/CanvasContext.h>
24 #include <shaders/shaders.h>
25 #endif
26
27 #include "utils/Color.h"
28
29 namespace android::uirenderer {
30
31 namespace {
32
33 // custom tonemapping only exists on Android devices
34 #ifdef __ANDROID__
35 class ColorFilterRuntimeEffectBuilder : public SkRuntimeEffectBuilder {
36 public:
ColorFilterRuntimeEffectBuilder(sk_sp<SkRuntimeEffect> effect)37 explicit ColorFilterRuntimeEffectBuilder(sk_sp<SkRuntimeEffect> effect)
38 : SkRuntimeEffectBuilder(std::move(effect)) {}
39
makeColorFilter()40 sk_sp<SkColorFilter> makeColorFilter() {
41 return this->effect()->makeColorFilter(this->uniforms());
42 }
43 };
44
createLinearEffectColorFilter(const shaders::LinearEffect & linearEffect,float maxDisplayLuminance,float currentDisplayLuminanceNits,float maxLuminance)45 static sk_sp<SkColorFilter> createLinearEffectColorFilter(const shaders::LinearEffect& linearEffect,
46 float maxDisplayLuminance,
47 float currentDisplayLuminanceNits,
48 float maxLuminance) {
49 auto shaderString = SkString(shaders::buildLinearEffectSkSL(linearEffect));
50 auto [runtimeEffect, error] = SkRuntimeEffect::MakeForColorFilter(std::move(shaderString));
51 if (!runtimeEffect) {
52 LOG_ALWAYS_FATAL("LinearColorFilter construction error: %s", error.c_str());
53 }
54
55 ColorFilterRuntimeEffectBuilder effectBuilder(std::move(runtimeEffect));
56
57 auto colorTransform = android::mat4();
58 const auto* context = renderthread::CanvasContext::getActiveContext();
59 if (context) {
60 const auto ratio = context->targetSdrHdrRatio();
61 if (ratio > 1.0f) {
62 colorTransform = android::mat4::scale(vec4(ratio, ratio, ratio, 1.f));
63 }
64 }
65
66 const auto uniforms =
67 shaders::buildLinearEffectUniforms(linearEffect, colorTransform, maxDisplayLuminance,
68 currentDisplayLuminanceNits, maxLuminance);
69
70 for (const auto& uniform : uniforms) {
71 effectBuilder.uniform(uniform.name.c_str()).set(uniform.value.data(), uniform.value.size());
72 }
73
74 return effectBuilder.makeColorFilter();
75 }
76
extractTransfer(ui::Dataspace dataspace)77 static ui::Dataspace extractTransfer(ui::Dataspace dataspace) {
78 return static_cast<ui::Dataspace>(dataspace & HAL_DATASPACE_TRANSFER_MASK);
79 }
80
isHdrDataspace(ui::Dataspace dataspace)81 static bool isHdrDataspace(ui::Dataspace dataspace) {
82 const auto transfer = extractTransfer(dataspace);
83
84 return transfer == ui::Dataspace::TRANSFER_ST2084 || transfer == ui::Dataspace::TRANSFER_HLG;
85 }
86
getDataspace(const SkImageInfo & image)87 static ui::Dataspace getDataspace(const SkImageInfo& image) {
88 return static_cast<ui::Dataspace>(
89 ColorSpaceToADataSpace(image.colorSpace(), image.colorType()));
90 }
91 #endif
92
93 } // namespace
94
95 // Given a source and destination image info, and the max content luminance, generate a tonemaping
96 // shader and tag it on the supplied paint.
tonemapPaint(const SkImageInfo & source,const SkImageInfo & destination,float maxLuminanceNits,SkPaint & paint)97 void tonemapPaint(const SkImageInfo& source, const SkImageInfo& destination, float maxLuminanceNits,
98 SkPaint& paint) {
99 // custom tonemapping only exists on Android devices
100 #ifdef __ANDROID__
101 const auto sourceDataspace = getDataspace(source);
102 const auto destinationDataspace = getDataspace(destination);
103
104 if (extractTransfer(sourceDataspace) != extractTransfer(destinationDataspace) &&
105 (isHdrDataspace(sourceDataspace) || isHdrDataspace(destinationDataspace))) {
106 const auto effect = shaders::LinearEffect{
107 .inputDataspace = sourceDataspace,
108 .outputDataspace = destinationDataspace,
109 .undoPremultipliedAlpha = source.alphaType() == kPremul_SkAlphaType,
110 .type = shaders::LinearEffect::SkSLType::ColorFilter};
111 constexpr float kMaxDisplayBrightnessNits = 1000.f;
112 constexpr float kCurrentDisplayBrightnessNits = 500.f;
113 sk_sp<SkColorFilter> colorFilter = createLinearEffectColorFilter(
114 effect, kMaxDisplayBrightnessNits, kCurrentDisplayBrightnessNits, maxLuminanceNits);
115
116 if (paint.getColorFilter()) {
117 paint.setColorFilter(SkColorFilters::Compose(paint.refColorFilter(), colorFilter));
118 } else {
119 paint.setColorFilter(colorFilter);
120 }
121 }
122 #else
123 return;
124 #endif
125 }
126
127 } // namespace android::uirenderer
128